The cornea is the clear outer surface of the eye that covers the iris and pupil. It is the structure through which light passes to reach the retina. Keratitis is the inflammation of one of the layers of the cornea. Keratitis is a serious ocular disease that can lead to many complications if not treated early, including corneal scarring and even blindness. Patients with keratitis should be evaluated and treated promptly by an ophthalmologist.
The incidence of keratitis is higher amongst contact lens wearers. Fungal keratitis and ulcers are more common in developing countries. Keratitis is a vision-threatening condition, therefore expeditious treatment plays a key role in its prognosis.
Types of keratitis
- Bacterial keratitis
- Viral keratitis
- Fungal keratitis
- Autoimmune causes
- Rheumatoid arthritis
- Sjogren's syndrome
Causes of keratitis 1
Damage to the corneal epithelium/surface or the lack of a normal tear film allows the microorganisms to enter the cornea and proliferate. This leads to inflammation and possible infection. Microorganisms either gain entry from damaged areas of the cornea or penetrate the intact corneal surface directly. They proliferate and initiate ulcer (infection) formation.
Causes of infectious keratitis include bacteria, fungi, helminths, and viruses. The noninfectious causes may include injury, contact lenses, post-surgical scars, and dryness of the eye.
Signs and symptoms of keratitis
The most common complaint that patients present with is irritation in the affected eye. The other signs or symptoms of keratitis may include:
- Redness of the affected eye
- Blurred vision
- Foreign body sensation
- Excessive tearing
- Sensitivity to light
Diagnosis of keratitis 1,2
Your ophthalmologist will take a detailed history and perform a complete eye examination to make a diagnosis of keratitis. Investigations may include:
- Details of presenting complaint
- History of contact lens wear and details of use
- History of any injury or trauma to the eye
- History of any underlying systemic diseases
- Previous history of ocular diseases
- Test of visual acuity and intraocular pressure
- Slit lamp examination including dilated exam
- To assess extent and progression of the disease
- Corneal scrapings
- Your healthcare provider may take a sample of the corneal ulcer and its edges by using a sterile swab or blade.
- This sample will be examined microscopically to identify infectious agents e.g bacteria or fungi.
- Culture of tears and samples from contact lenses may also be taken.
- In mild cases of keratitis, this may be deferred.
- Laboratory investigations
- Complete blood count
- C reactive protein
- Antibody profile in cases of suspected autoimmune disease
- Ocular ultrasound may also be advised in severe cases
Management of keratitis 1,2
Treatment of keratitis depends on the eradication of the causative agents or treatment of the underlying systemic disease.
- Proper ocular hygiene especially with regards to contact lens usage
- Topical antibiotics are routinely used to treat bacterial keratitis e.g fortified topical antibiotics.
- Topical antifungals are advised if the underlying cause is fungal.
- Antivirals (topical and/or oral) if the underlying cause is viral.
- Topical steroids (used with caution)
- Correction of local causes e.g entropion or misdirected eyelashes.
- Treatment of autoimmune conditions e.g rheumatoid arthritis.
- Topical steroids
- Oral steroids
- Oral immunosuppressants
- Surgical interventions may be needed in cases of corneal perforation or aggressive ulcers.
- Applications of adhesive tissues
Patients with keratitis are usually advised to have close follow-up for the monitoring of vision and clinical status.
Complications of keratitis
Corneal ulcers usually take days or weeks to heal but early diagnosis and treatment may hasten the resolution. Irreversible vision loss may be prevented by prompt treatment and close follow-up. If a patient presents late or treatment gets delayed then the following complications may occur:
- Corneal scarring
- Corneal perforation
- Glaucoma second to keratitis
- Corneal fistula
- Deschênes, J., MD. (2022, March 9). Bacterial Keratitis: Background, Pathophysiology, Epidemiology. https://emedicine.medscape.com/article/1194028-overview
- NCBI - WWW Error Blocked Diagnostic. (n.d.). https://www.ncbi.nlm.nih.gov/books/NBK559014/
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